I sometimes think we live in different worlds :^) Here's our EF nmr coil
Q's also close to 100, but at 2-3 kHz. I think there are something like 1,000 turns of seven strand litz wire.
George H.
On Wed, 12 Aug 2015 07:15:50 -0700 (PDT), George Herold Gave us:
His links work. Yours pukes.
Huge coils can get high Qs. I've done pot cores with litz wire that hit 250 or something like that at audio frequencies. Surface mount at
10s of MHz is harder.Coilcraft has a q-finder app online. Surface mount parts might hit 70 or so, a few impractically-low-L parts in the 200 ballpark, but some are in the single digits. I think the PCB ground planes get involved, too.
-- John Larkin Highland Technology, Inc lunatic fringe electronics jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Worked fine for me.
Are you at work? Some companies block Dropbox. Some of my customers block so much stuff, guys take a laptop to Starbucks to download my files. I ship things to their homes, too, so they don't get lost in Warehouse 99.
-- John Larkin Highland Technology, Inc lunatic fringe electronics jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
:
on.
s.pdf
lly, COG ceramics had excellent properties, but got too big to be useful at much over 100pF. Dielectrics offering a higher dielectric constant tended to have compensating defects.
of +/-30ppm/K
d as the dielectric.
. 05-1-ND/3845702ng faster with temperature once you get away from there, and it's not spell ed out all that clearly.
away.
witched
o.
been identified.
a useful observation.
s than helpful. You need a part number you can stick on a data sheet that w ill always call up the same part - the buyers always want to buy something almost the same that the rep swears is just as good ...
I've just installed SuSE 13.2 on a second hard disk, and I'm trying to dow nload Kicad. The circuit is simple enough that a PCB layout is going to be faster (and a lot more reliable) than hand-wiring a board.
me session. The web claims that disabling IPv6 can solve the problem - whic h it doesn't - and finding the right mirror can solve the problem - which i t does until you try and download Kicad (which looked as if it was going to work fine until Yast2 started finding its dependencies).
work-around - all advice gratefully received.
It turned out that SuSE 13.2 installs with links to software repositories t hat don't work - nine of them. I've now trawled through a bunch of SuSe 13.
2 mirrors to find links that do work - about five so far - and Kicad is ins talled and looks as if it might be working. It's now 1:15am in Sydney, so I 'll go to bed rather than finding out how user-friendly it actually is.-- Bill Sloman, Sydney
Odd. George Herold's dropbox link worked fine for me, and the image was comprehensible. John Larkin's offerings were a bit harder to process.
-- Bill Sloman, Sydney
This is a good use for a smart phone.
:
e:
lon.
rs.pdf
Hi George - one of the plausible applications of my low distortion sine wav e oscillator is in earth-field nmr. One of the the earlier variations was a n LC oscillator, but with even heavily ferrite-cored inductors the harmonic spikes from the hysteresis in the ferrite were only going to be 105dB belo w the fundamental. Your air-cored coil has probably got enough inductance t o be resonated at around 2kHz, which may have some interesting implications .
E-mail me at snipped-for-privacy@ieee.org from an e-mail address that doesn't rejec t everything as spam, and I'll expand on the point.
-- Bill Sloman, Sydney
On Wed, 12 Aug 2015 21:19:07 -0700 (PDT), Bill Sloman Gave us:
Don't need litz at that frequency.
3kHz is the standard for mining applications. Penetrates ground.Bobbins are too small. Bigger loops are better.
AlwaysWrong strikes again. George is talking about earth field nuclear magnetic resonance. It's a teaching laboratory toy, not a mining probe, and the proton resonant frequency at magnetic fields from 30 to 60 microtesla varies from 1.3kHz to 2.5kHz.
The sample sits inside the coil, so a bigger loop wouldn't be better.
He may not need litz, but it may offer enough advantage even at that low frequency to be useful in his - rather unusual - application.
-- Bill Sloman, Sydney
On Thu, 13 Aug 2015 01:51:40 -0700 (PDT), Bill Sloman Gave us:
The fact that you started out with this stupid shit...
Makes you nothing but a stupid shit.
Sadly, the stupid shit is all yours, and the StupidShit title with it.
You should have stuck with AlwaysWrong. If you really thought that I'd got it wrong - as opposed to catching you with your pants down - you'd be able to explain why I was wrong, as opposed to snipping the argument that demonstrated how you'd got it wrong.
-- Bill Sloman, Sydney
On Thu, 13 Aug 2015 07:41:20 -0700 (PDT), Bill Sloman Gave us:
You're a goddamned retard on par with Donald Trump.
And I was right. Litz wire is not needed at such a low frequency.
Miners do operate at those frequencies.
And I was trying to be nice and you chimed in with bullshit. You are about as stupid as it gets.
Why are looking at DA? You should be looking at Q.
On Thu, 13 Aug 2015 14:26:09 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:
snip
Look at mica!
More brains and less money ...
You think you are right, but you are AlwaysWrong. Litz wire may not be "needed" but it may offer a small but useful advantage in the application - which you clearly know nothing about.
And TeachSpin, where George Herold works (nice photo of him on the web-site)
doesn't seem to sell stuff to miners.
You thought that you were being nice, but you are AlwaysWrong. If there were a competition for being as stupid as it gets, you'd be in there with a strong chance, though krw might well pip you at the post.
Try and make your mindless abuse a trifle less mindless, and do work out what the abbreiviation "nmr" - for nuclear magnetic resonance actually means.
First you make an idiot of yourself, and now you are trying to deny that you made an idiot of yourself by throwing up a cloud of implausible abuse. Grow up.
-- Bill Sloman, Sydney
On Thu, 13 Aug 2015 19:32:14 -0700 (PDT), Bill Sloman Gave us:
"may offer"?
It is more than clearly obvious that you are the one who clearly knows nothing about it.
I, however, work with it on a daily basis.
His radiating coil is nothing more than an antenna.
You obviously spent some time too close to one which was 'keyed up' being driven by a few kW of HF RF.
It shows, Slowboy. The shame is that it didn't kill you. Hopefully it trounced your nads though. The last thing the gene pool needs is your bloodline in it.
On Thu, 13 Aug 2015 19:32:14 -0700 (PDT), Bill Sloman Gave us:
You really should refrain from looking in a mirror when you post here.
You've got a mirror next to the computer you use when posting stuff to s.e.d.?
Makes sense for a janitor, I suppose. And John Larkin probably has one too.
I don't. The only idiot around here is you, and you go to a great deal of trouble to make it obvious.
-- Bill Sloman, Sydney
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.